Calculating device



F. J. MCNAMARA 2,268,886

CALCULATING DEVICE Filed Oct. 17, 1959 ATTA/EV.

jan. 6, 1942 UNITED STATES PATENT OFFICE CALCUIATING DEVICE Frank J. McNamara, Buffalo, N. Y. Application October 17, 1939, Serial No. 299,858

(Cl. 23S-83) 7 This invention relates to improvements in calculating devices of the type including a graduv, ated disk and a pair of hands or indicators adjustable to be set in accordance with graduations on the disk. This invention relates more particularly to means for adjusting the hands or indicators relatively to each other and to the disk.

One of the objects of this invention is to provide a calculating device of this kind having improved means for adjusting the arms or indicators relatively to each other and to a disk. Another object is to provide a device of this kind in which the disk is rotatably adjustable relatively to the indicators. whereby the operation of the calculating device is greatly facilitated. A further object is to provide an improved clutch mechanism by means of which the disk and indicators may be releasably held in frictional engagement with each other to facilitate rotary adjustment of the disk and indicators relative to each other. Another object of this invention is to provide a calculating device of this kind with a holding member having one of the hands or indicators secured thereto and having the other hand or indicator held in frictional engagement therewith. A further object is to provide a calculating device having a holding member on which the hands or indicators are mounted, and which may be clutched to or declutched from the disk.

A further object is to provide a device of this kind with an indicator assembly consisting of a holding member having one of said indicators secured thereto and having said other indicator held in frlctional engagement therewith to facilitate rotary adjustment of said indicators relatively to each other.

Other objects of this invention will appear fromthe following description and claims.`

In the accompanying drawing:

Fig. 1 is a plan view of a calculating device embodying this invention and of the disk on which only a portion of the graduations are shown.

Fig. 2 is a fragmentary plan view thereof, showing the hands or indicators in dierent positions relatively to the disk.

Fig.- 3 is a fragmentary central sectional ele- The calculating device includes a graduated s plate or disk l0 which may be of any desired form. that shown being circular. 'Ihe disk is preferably composed of a rigid basic material having a comparatively flexible material secured to one or both faces thereof. A disk of unitary structure may, however. be employed. The bottom face of the disk may be provided with desired reference data thereon and the top face of the disk may be provided with any number and types of mathematical scales thereon. The scales are preferably arranged concentrically about a central point on thedisk having the extremities of each scale coinciding with a radial line assumed to extend outwardly from the ccn-J tral point.

Each scale may be represented by a series oi short radial graduations spaced at annular intervals according to the predetermined decimated portions of the scale and designated according to the type and purpose thereof. The designations are preferably arranged with their top extremities outermost from the central point. For example, in the construction illustrated, Il partially represents a scale having graduations spaced at equal annular intervals. and I2 partiallyl represents a second scale having graduations spaced at annular intervals according to a logarithmic scale. Any additional scales may be provided. such as partially represented at I3 and I4 and indicated by broken circular lines at Ii and I6. Scales of this type are well known in connection with slide rules and other calculating devices for various uses, such for example as adding and subtracting, multiplying and dividing, proportions, percentages, reciprocals, common and natural logarithms of numbers, roots and powers of numbers, trigonometric functions of angles and any desiredcombinations thereof.

Calculating devices of this kind have heretofore been provided with a pair of hands or indicators which are pivoted to rotate about the central point of a disk and relatively to each other to act more or less in the nature of dividers. Two such hands or indicators Il and Il preferably made of transparent material are shown on the accompanying drawing, and each is provided with a hairline 2| formed lengthwise thereon. These hands or indicators are preferably arranged with the hairlines adjacent to the top face of disk Il and extend radially from an axis which passes through the point about which the scalesarearranged ondisk-lil.

. It is desirable in connection with the use of thisdevieetoreadilyadiustthehandsorindicators Il and 20 relatively to each other and to the disk i 8, and this adjustment is facilitated in the construction illustrated by making one of the' hands shorter than the other. In the particular construction illustrated, the hand I8 terminates within the periphery of the disk or plate I8, while the hand or indicator 2li extends beyond this periphery, so that the portion extending beyond the periphery may easily be manipulated for adjustment relatively to the other hand or indicator I8.

In order to facilitate the use of thecalculating device, I provide suitable holding means, such as a centrally arranged knob or handle 24 which may be of any suitable or desired form and to which one of the hands, preferably the shorter hand I8 is rigidly secured while the longer hand or indicator 22 is frictionally held relatively to the knob 24 so that it may be turned about the knob. It is not essential that the hand I8 be immovably secured relatively to the knob 24, since it is suillcient if the short hand I8 is considerably more dilcult to turn relatively to the knob 24 than the hand 28. The knob 24 is Aconstructed so vthat the disk or plate I8 may swing relatively to the knob and' a releasable clutch is preterably provided for this Purpose, the clutch being so constructed that when released, the disk may turn freely relatively tothe knob, and when the clutch is in engaging position, the disk will be frictionally heldin iixed relation to the knob.

Any suitable or desired means for carrying out this relationship between the knob or holding member, the disk and the two hands may, of course, be employed. In the construction illustrated, I have shown by way of example. one embodiment of my invention. but it is understood that it Is not intended to limit this invention to the particular construction shown.

The holding member, such'for example as the knob o'rvhandle 24, may, of course, be of any suitable or desired shape for conveniently holding the calculating device during the use of the same, that shown having a shank 25 provided with an enlargement or flange 21 at the outer end thereof so that the knob may be easily held between two lingers of a hand. The knob is provided with an extension or insert 22 which may be formed integral therewith, and which extends below the shank portion thereof. In

the particular construction illustrated, an extension 28 is formed separately and pressed into tightly fitting engagement in a central aperture or handle 24, or the knob may be molded about the extension or insert. By making these two parts in separate pieces, the concentric machining of the extension or insert 28 is facilitated to ensure concentricity of the bore of this extension 28 with the periphery thereof and with the portion 28 thereof, and also the knob or'handle 24 may be made of a non-metallic material or composition, while the extension 28 thereof may be in the form oi a metal sleeve or hollow cylinder. The extension 428 is of smaller diameter than the shank 25 of the knob and extends below the same as shown in Figs. 3 and 4, thus forming therewith an annular shoulder, and extension 28 is also provided at its lower end with a portion 28 of reduced diameter, thus forming another shoulder.

The long hand or indicator is provided with an aperture which ts snugly about the portion of the extension 28 above the reduced portion 28, the t being such that the hand 22 may be turned about the knob and the extension 28. 22

represents a spring washer which is interposed between the long hand 22 and the shoulder formed by the lower end of the shank 25 of the knob, the .spring washer yieldingly engaging the long hand or indicator 20.

The short hand or indicator I8 may be rigidly secured to the knob or handle 24 in any suitable or desired manner, and in the construction illustrated, this hand is provided with an aperture through which the portion 28 of reduced diameter extends. A pair of disks or washers 22 and 24 `are arranged above and below the hand or indicator I2 and also fit on the portion 22 of reduced diameter. In order to secure the hand or indicator I8 on the knob or handle,l the outer or lower end of the reduced neck Portion 22 may be riveted or swaged over so as to bind the washers 22 and 24 and the short hand I8 securely on the neck portion 28 of the extension 22. When these parts are assembled in this manner, it will be noted that the upper washer 22 also forms a bearing 'surface against whichthe lower face of the longer hand 28 is forced into frictional engagement by means of the spring washer 22. Any other means for securing the short hand I8 on the knob orhandle may, of course, be employed.

The extension or insert 28- o f the knob or handle 24 is provided with a central bore or aperture in which a pivot pin 25 is slidably arranged. This pivot pin also extends through the central aperture in the disk I8. in such a manner that the disk may rotate freely about the pivot pin 25. The lower end of the pivot pin has a friction disk or washer 21 rigidly secured thereto in any suitable or desired manner, for example, by forming the end of the pivot pin of reduced diameter to extend through an aperture inthe friction disk or washer 21. The end of this reduced portion of the pivot pin may then be riv,` eted or peened over as indicated at 28, so that the friction disk or washer 21 will be rigidlyl secured to the pivot pin 25 and will bear against n the underface of the disk or plate I8.

or bore 4I extending axially through the knob The means provided for frictionally holding the disk or clutch member 21 yieldingly and releasably in engagement with the disk I8 are,- in the particular construction illustrated, formed as follows: The pivot pin 25 extends above the extension 28 of the knob or handle 25 into an aperture 4I thereof, which Is of larger internal diameter and the pivot pin is provided at its upper end with an enlargement such, for example, as a button or nut 48, the upper end of which extends beyond the top surface of the knob or handle 24. The button 48 may be secured in any suitable manner to the pivot pin, for example. by providing a screw thread at the upper end of the pivot pin which may engage with an internal screw thread on the button 42.

The button is formed to slidably fit the aperture 4I extending through the knob or handle 24, and a coil spring 42 is interposed between the button and the upper end of the extension 28. It will thus be seen that the spring 42 yieldingly urges.` the pivot pin 25 in an upward direction, thus causing the friction disk or washer 21 -to be urged into frictional engagement with the bottom surface of the disk or plate I8. When the button 40 is pressed against the action of the spring 42 into the recess or aperture 4I lof the knob` 24, the pivot pin 25 will move downwardly so that the friction disk or'washer21 moves out of gripping engagement with the disk or plate l,th makingitpoibleicrrthisplate ordisk to turn about the 'pivot pin.

use .my improved calculating device, knob 24 is preferably held between the middle index ngers o! thehand with the thumb positioned against the button 4l. The device is preferably held in sucha manner that the short hand Il which is secured to the knob extends upwardly or away from the user. This manner oi holding has the advantage that the numbers or designations on the scales will always be in an upright position on the top portion of the disk when held in front ofthe user, which greatly facilitates the use of the calculating device.` In the use of the device, the button II is then pressed inwardly by the thumb so that the disk In may be rotated so that the desired graduation thereon is directly under the hairline 2I of the short hand I0. When this has been done, the pressure on the button Il i8 released, thus clutching the hand Il to the disk in the desired position. The longer hand 20 may then be moved to another graduation on the disk, by pushing the outer end thereof projecting beyond the periphery of the disk and moving the same about the knob 24 and the disk I0. This adjustment oi the long hand 20 is made possi-ble by the fact that this hand is held frictionally on the knob by the spring washer 32, and adjustment of this hand is effected while the short hand I8 is clutched to the disk. Consequently, relative movement of the long hand about the knob or handle will not change the adjustment of the short hand relatively to the disk. In this manner, the two hands or indicators I8 and 20 are positioned at the desired angle relatively to each other. In order to move both hands simultaneously, the button Il is pressed, and the disk may then be rotated to place the desired graduation under either hairline.

For example, if it is desired to multiply '1 by 8, the button 40 is pressed and the disk I0 turned until the hairline on the short hand Il lies in registration with the graduation designated by the number 'l on the scale I2. When this hairline is correctly positioned, pressure on the button 40 is released so that the short hand It is clutched to the disk Il. The long hand 2li is then moved about the knob 2l until the hairline thereon lies over the graduation designated by the number 10 on scale I2. 'Ihe parts will then be in the position shown in Fig. l. When this has been done, the button l is again pressed and the disk turned until the hairline on the hand or arm 20 registers with graduation designated by the number 8 on scale I2, as shown in Fig. 2. When this is done, it will be noted that the hairline on short arm Il indicates the answer 56 on scale I2. 1

I claim as my invention:

l. A calculating device comprising a plate having a series of mathematical graduations arranged thereon about an axis, a pair of indicators extending radially across the graduated face of said plate, a holding member on which said plate is mounted to swing about said axis, one of said indicators being mounted on said holding member to normally move therewith and the other indicator being frictionally held on said holding member to turn about the same relatively to said iirst mentioned indicator, and means extending through said holding member and operable at will for locking and unlocking said plate relatively to said holding member.

ing a series of 'mathematical graduations arrangedthereonaboutanaxis,apaircfindi cators extending radially across the graduated face of said plate, a holding member having a pivot member on which said plate is mounted to rotate about said axis, a clutch member for frictionally gripping said plate to hold the same against rotation about said pivot member, means operable for releasing said clutch member from engagement with said plate, means for rigidly securing one of said indicators to said holding member, and means forfrictionally holding said other indicator for rotary adjustment about said holding member.

3. A calculating device comprising a plate having a series of mathematical graduations arranged thereon about an axis, a pair of indicators extending radially across the graduated lace of said plate. a holding member, a pivot pin extending through said holding member and on which said plate is mounted to rotate about said axis, a friction disk secured on said pivot pin, means normally urging said pivot pin into a position in which said friction disk engages said plate for holding the same against movement relatively to said holding member, said pivot pin ybeing movable axially relatively to said holding member to move said friction disk out of frictional engagement with said plate, means for rigidly securing one of said indicators on said holding member, and means for frictionally supporting said other indicator on said holding member for rotary movement about the same.

4. A calculating device comprising a plate having a series of mathematical graduations arranged thereon about an axis. a pair of indicators extending radially across the graduated face of said plate and mounted to swing about said axis, a holding member having a shouldered extension to which one of said indicators is rigidly secured, means on said holding member for yieldingly urging the other of said indicators into frictional contact at one side of said rst mentioned indicator, means for yieldingly urging said plate toward the other face of said first mentioned indicator for frictionally securing said plate and nrst mentioned indicator in the desired relationship toweach other, and means for releasing said frictional engagement between said plate and said iirst mentioned indicator during the use of said device.

5. A calculating device comprising a plate having a series of mathematical graduations arranged thereon about an axis, an indicator assembly mounted on said plate to turn about said axis, and including a holding member, an indicator arranged in iixed relation to said holding member, and a second indicator mounted on said holding member and adjustable relatively thereto, means for normally clutching said indicator assembly and said plate to each other, and means operable during the use of said device for declutching said assembly and plate.

6. A calculating device comprising a plate having a series of mathematical graduations thereon arranged about an axis. an indicator assembly mounted on said plate to turn about said axis, and including a holding member, an indicator carried by said holding member, a second indicator mounted on said holding member, each of said indicators extending into operative relation to said graduations, said second indicator being readily adjustable relatively to said holding member and to said first indicator to enable said 2. A calculating device comprising a plate havsecond indicator to be moved into various angular relations to said nrst indicator in accordance with said graduations, Aa pivot arranged concentric with said axis and connecting'said plate and indicator assembly, means for normally clutching said indicator assembly and said plate to each other, and means operable during the use of said device for .declutching said assembly and plate, to permit both indicators to be moved relatively to said graduations without changing the spacing of said indicators relatively to each other.

7. A calculating device comprising a plate having a series oi mathematical scales arranged thereon about the axis of a hole therein.- an indicator assembly including a holding member, an

indicator arranged in iixed relation thereto, and 15 cator assembly.

a second indicator mounted on said holding member, each of said indicators extending into operative relation to said graduations, said second indicator being readily adjustable about said indicator assembly about the axis of said hole in said plate and relatively to said ilrst indicator to enablesaid. second indicator to be moved into various angular relations to said first indicator in accordance with said scales, a part pivotally connecting said indicator assembly and said plate and fitting snugly in said hole in said plate for axial alinement of said indicator assembly with said hole in said plate, means tor normally clutching said plate and indicator assembly to each other, and means operable during the use of said device for declutching said plate and indi--` FRANK J. MCNAMARA. 

